install Eko 25 to existing system, need help

[CANUCK GLAZIER]

Hey all!!

I am in the process of buying an Eko 25(Zenon from New Horizon said it should handle my heating and DHW needs).

Currently I am using an oil fired hot water tank(Aero 32 gl.) to supply 2500 sqft radiant floor and DHW. I am not planning storage right away but maybe in the future. My question is this...... I would like the most practical and easiest (glazier proof lol) way to install the Eko 25. My radiant floor is a closed system with a HX. One pump from the hot water tank to Hx and one pump for the floor system (Rehau adjustable zones for each room. I've been reading quite a bit on different topics in the boiler room, but I think I'd like some opinions specific to what I'm doing. Any help would be appreciated as I would like to install this myself if possible.

Rob

 

[CANUCK GLAZIER]

C'mon boilers!!

Someone must have some ideas......please

Rob

 

[Anything Plumbing]

Because a oil fired water heater is used for domestic hot water and not for space heating you have a problem to start. A wood boiler is made to heat a boilers water so that the burner never turns on and you save $. In your case again you would need a Hx and 2- circs to get the wood boiler to even heat that oil fired WH. That starts more problems you might notice the wood boiler is not scrubbing enough heat off and will over heat. Enough storage could help fix that. Another instance is that the cold domestic water being used is coming at a cold temp and the Hx might not heat the water fast enough to stop the burner from turning on or short cycling. I wouldn't suggest putting a wood boiler in that scenario honestly. I would put in a oil or propane boiler with a coil or indirect for domestic first then a wood boiler.

 

[Nofossil]

I wouldn't be quite so pessimistic, but this does raise some interesting challenges. Is it possible to heat your water tank to higher temperatures without causeing problems? You'd need a mixing valve to prevent scalding for the DHW, but you's also have to ensure that the radiant is OK.

The EKO won't be happy if the incoming water is below 130 for extended periods, and it will provide about a 20 degree boost. As mentioned above, you'd need another HX at a minimum, perhaps in the existing tank <-> radiant loop. Then, you'd need to ensure that the potable water circ runs whenever the EKO circ is running.

My sense is that you'll have a hard time dumping 60,000 BTU/hr, so the EKO will idle and is likely to overheat your Aero tank at least a bit.

 

[CANUCK GLAZIER]

Hey guys,

Thanks for the replies!!

Right now my oil fired Aero supplies my heat for the radiant floor( which as I said is a closed system with a HX because it is code where i live that the domestic water never comes in contact with the floor water) and it supplies my DHW.

Here's what I've been wondering do I just use my oil fired for DHW and let the wood boiler heat the floor in the cold months or do I try to use the wood boiler as a source of DHW as well?

Nofossil I was on ur sight WOW! lots of data and ideas. I was hoping you'd respond to either my email I sent you via ur site or to this thread.

I really would like to hook the 25 and the oil fired Aero in series if at all possible. What do you think?

I've already ordered the eko 25 it will arrive mid August, so I have from now till then to figure out a game plan.

Thanks in advance for considering your help

Rob

 

[Nofossil]

You can't really do classic series installation because you can't run potable water through the EKO. Best you could do is add another flat plate HX in the loop that goes from the Aero to the radiant HX. The EKO would need its own isolated water in this case, but it would then be able to heat both your floor and your DHW. Read my post above about mixing valves ond overheating the Aero. If you look at my site, I overheat my DHW but you need to add mixing valves to prevent scalding.

 

[CANUCK GLAZIER]

Thanks Nofossil,

I checked my Aero and there already is a mixing valve in place ( again code here) on the DHW supply as the tank is set to the highest setting. How hot do you get the water in ur tank? Is there a standard set for safety on most tanks with the relief valve?

The only reason for no storage was space limitations in the room for the eko. What is the smallest amount of storage that would benefit the system? What if I had room for even just a couple more used hot water tanks? Could I use them for storage? I prob have room for two tanks may be three.

I'm starting to see how it would connect together, its just getting my head around where to splice into the existing set up.

Rob

 

[Nofossil]

Thanks Nofossil,

I checked my Aero and there already is a mixing valve in place ( again code here) on the DHW supply as the tank is set to the highest setting. How hot do you get the water in ur tank? Is there a standard set for safety on most tanks with the relief valve?

The only reason for no storage was space limitations in the room for the eko. What is the smallest amount of storage that would benefit the system? What if I had room for even just a couple more used hot water tanks? Could I use them for storage? I prob have room for two tanks may be three.

I'm starting to see how it would connect together, its just getting my head around where to splice into the existing set up.

Rob

I heat my DHW to 160 degrees. What's the highest setting on your Aero? 32 gallons seems pretty small - your oil burner must cycle on and off a lot when you're using the radiant.

I guess the answer is that any storage is better than no storage, but realistically you start to get real benefits when the storage is large enough to carry the house for a significant portion of a day. In general, 500 gallons is considered the minimum useful storage for space heating. However, a couple of extra hot water tanks could extend your DHW for days. Could you put additional storage elsewhere?

 

[CANUCK GLAZIER]

I prob could do an out building for storage possibly attached to the house, but that would just add extra expense that I cant really afford right now. Like you said some storage would be better than no storage. As far as the 32 gal oil fired tank cycling on and off alot, it does when it is very cold.

I was inspired by Eric's(moderator) use of his eko with no current storage. Of course it goes without saying it will not be as efficient compared to having storage. But certainly will save us about 2-3 tanks of oil this winter. Next year I could look into and tackle financially the storage problem.

The wood I am getting is basically free except for alot of labour.

Would I still keep the boiler basically a closed system if I try the multiple used hot water tanks?

Rob

 

[Nofossil]

You could circulate boiler water through the storage tanks, or you could circulate potable water. I'm not sure that it makes much difference.

I ran for a season without storage. Worked fine, but we had to be really careful to avoid running out of hot water. Had to build more fires.